Dermatology Clerkship

1. Genetic Diseases
Section of Dermatology
Department of Medicine
UWI
Prepared by Dr. Althea East-Innis

2. Genetic Diseases
 Tuberous sclerosis
 Neurofibromatosis

3. Tuberous Sclerosis (Epiloia)
 Autosomal dominant inherited neurocutaneous
disorder
 Characterized by seizures, mental retardation
and skin manifestations with variable
expressivity
 Given the eponym epiloia – epilepsy, low
intelligence and adenoma sebaceum

4. Tuberous Sclerosis (Epiloia)
 ½ have normal intelligence.
 ¼ do not have fits.
 The cutaneous changes may be the only
presenting symptom.
 Hamartomas are described in nearly all organ
except skeletal muscles.
 Both sexes are affected equally.
 60% are a result of mutations.

5. Tuberous Sclerosis (Epiloia)
 There are 5 skin stigmata:
An ovoid ash-leaf patch of hypopigmentation
Adenomata sebaceum (angiofibromata)
Periungual fibromata
Shagreen patches (connective tissue naevi)
Fibromatous nodules

6. Ash-leaf Patch
 Appears during infancy
 Differs from vitiligo in that
melanocytes are present
in normal numbers but
contain few
melanosomes

7. Adenomata Sebaceum
(Angiofibromata)
 Appear in childhood from
5 years onward
 Occur on the face
around the sides of the
nose but may also occur
on the chin, cheeks and
forehead

8. Periungual Fibromata
 These appear later after
puberty.

9. Shagreen Patches
 Connective tissue naevi
on the trunk, usually the
lumbosacral region.

10. Fibromatous Nodules
 Occur on the forehead or scalp.

11. Management
 Diagnosis is usually straightforward.
 Computerized axial tomography aids diagnosis
as intraventricular calcified nodules may be
found even in infants
 No specific treatment but genetic counselling is
essential.

12. Neurofibromatosis
 A variety of neurocutaneous syndromes
associated with:
café-au-lait macules
axillary and perineal freckling
Lisch nodules
Neurofibromata
other abnormalities

13. Neurofibromatosis
 Dominantly inherited
 Occurs in approximately 1 in 3000 births
 At present there are 8 varieties

14. Neurofibromatosis – Clinical
Features
 Café-au-lait patches (6 or more necessary for
the diagnosis)
 Axillary and perineal freckling (Crowe’s sign)
 Lisch nodules (dome-shaped, translucent
papules up to 2 mm in size in the iris)
 Neurofibromata of the skin

15. Café-au-lait Patches

16. Axillary & Perineal Freckling
(Crowe’s Sign)

17. Lisch Nodules

18. Neurofibromata

19. Neurofibromatosis – Systemic
Features
 Intracranial neurofibromata of cranial nerves,
spinal cord or peripheral nerves
 Sarcomatous change may occur in any
neurofibroma
 Many other associated disorders are described,
particularly endocrine and bony defects

20. Management
 Genetic counselling.
 Investigate and follow-up for underlying
endocrine disorders and bony defects.
 Follow-up for malignant change in lesions.
 Only remove lesions if bothersome or malignant
change suspected.